watchdog: Add driver for Intel OC WDT

Add a driver for the Intel Over-Clocking Watchdog found in Intel
Platform Controller (PCH) chipsets. This watchdog is controlled
via a simple single-register interface and would otherwise be
standard except for the presence of a LOCK bit that can only be
set once per power cycle, needing extra handling around it.

Signed-off-by: Diogo Ivo <diogo.ivo@siemens.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20250317-ivo-intel_oc_wdt-v3-1-32c396f4eefd@siemens.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>